Applied Mechanics and Materials Vol. 848

Abstract: This paper presents the effect of carburizing phenomena on the microstructure and weldability of tube coils in the ethylene heating furnace. A tube coil material was used the Ni-base alloy grade 35Cr-45Ni-Nb. The specimens obtained from three different height levels of carburized tube were tested. The results from the SEM-EDS and microstructure analyses show that the carbon was concentrated in carburized tube and deposited in the solid solution and chromium carbide compound. The prediction of new weldability in the carburized tube with Ni_eq/Cr_eq ratio can be used for welding repair in petrochemical industry.

Abstract: This study involves V-groove butt welding of CP Titanium to 304 stainless steel by the gas tungsten arc welding (GTAW) process without and with buttering layer at the 304 stainless steel base metal. ERCuSn-A and ERNiCu-7 were chosen as a filler metals. Investigations including visual testing (VT), microhardness testing and metallurgical analysis were carried out by means of variable welding parameters. The experimental results showed that using the ERCuSn-A filler metal without and with buttering layer, any surface defect was not observed in the dissimilar metals welded specimen but an underbead crack was found at weld metal adjacent to the Ti/weld metal interface. Using the ERNiCu-7 filler metal without buttering layer, linear porosity was observed at weldment. However, using ERNiCu-7 filler metal with buttering layer, defect-free welded specimen could be achieved. The results of EDS analysis indicated that at Ti/weld metal interface, Ti diffused from the Ti base metal to the weld metal. At 304 stainless steel/weld metal interface, Fe, Ni and Cr diffused from the 304 stainless steel base metal to the weld metal.

Abstract: In this study, the research team aimed to apply the use of biological capturing system of single cell algae, common microalgae species Chlorella sp. that have higher photosynthetic efficiencies in efficient capturing carbon dioxide. Here, , In the biological CO₂ capturing process, biogas was pumped to the water recycling culturing medium, only CO₂, not CH₄, could dissolved efficiently with the sprayer and recycling medium system. The results showed the microorganisms could resist to methane except H₂S and significantly induced at least 90-95% CO₂ removal efficiency and increased in Cholerella sp. biomass production within 7 day cultivation compared the system without CO₂ feeding (0.6 and 0.4 percentage (g/mL), respectively. Since the biological treatment approach was durable and could possibly further applied for treating flue carbon dioxide exhausted by power plant and fuel-types, and mitigating acid rain, heavy fuel oil, natural gas prevention.

Abstract: Since the green chemistry strategy of the use of biological process is well known for its safe, easy, nontoxic, biocompatible and especially environmental friendly to all users. Recently, more nanomaterials synthesized by the uses of plants and/ or microorganisms are applied in many areas such as electronics, nanotechnology. Especially they are used to synthesize novel materials with unique properties and purposes. In this study, the researchers aimed to isolate microorganisms with the capability in gold nanoparticles (AuNPs) synthesis from the sources that are from gold management process such as leaching and washing process in gold/ jewelry carving factory. Three isolated genera composed of bacteria, yeasts, fungi synthesizing intracellular AuNOs were obtained and characterized for their species by PCR amplification of rDNA genes and sequence analysis and comparisons. They were Pseudomonas sp., Verticillium sp., Aspergillus sp., and Saccharomyces sp. The factors including pH, temperature, reducing agents, duration of AuNP formation were determined. The predominantly extracellular gold formation as a major criterion for synthesis of AuNPs was also chosen. The obtained isolates can be certain potential in future practical application in harvesting AuNPs from the waste water in most gold carving factory.

Abstract: At present, charcoal briquette fuel, a source of heat energy and mostly made from agricultural waste materials, are popular in the markets because of their high constant heat output. It helps reduce pollution, and produce no sparks while burning, but varied due to different types of materials, burning protocols, temperature, and pressure used. In this study, the research team have studied the characteristics of high quality fuel briquettes for possible further development of standard indicators of briquette fuel production process. In the study, key factors of the Charcoal fuel features composed of high qualities of physical characteristics and electrical induction. Activated carbon and coconut shell charcoal types were showed to be great materials. The production process involved aerobic burning at 800-900oC for at least 3 hours, grinding and mixing with starch binder. The briquettes’ electrical conductivity was especially lower than 10 kΩ. High heat production was obtained at least 6000 Cal/g while ground charcoal possessed with the sizes were varied. Under microscopy, the charcoal particle sizes were in a range of 50-100 μm for 30-50% (w/w), size of 10-50 μm for 20-40% (w/w) and distinctive numbers of holes greater than 300 μ to 1 mm were rarely observed. Therefore, with key characteristics of charcoal briquette fuel, it could be further applied for development the indicator as well as instruments to measure the quality of the briquette.

Abstract: This paper presents a system of assistive technology based on video-oculography (VOG) control interfaces, namely “Ophapasai”. The system designed specifically for disabled people communicate with the people that surround them. The primary method of this system consists of a selection of pictogram buttons within the circular menu-augment on the screen, which used an inexpensive video-oculography device. The results indicate that Ophapasai was used to support a number of communication functions (100%). Furthermore, we also conducted an evaluation of performance for pointing video-oculography device with three participants of amyotrophic lateral sclerosis (ALS). The evaluation used throughput of standards for computer pointing devices as measurement of user performance in a multi-direction point and select task which found, participants can pointing and selection their overall mean throughput was 2.02 bits/s.

Abstract: This work presents development of chemiresistor gas sensor based on polyaniline (PANi) blending with poly(methyl methacrylate) (PMMA) thin film for identification of volatile organic compounds (VOCs) relevant to environmental monitoring. The investigated VOCs are including acetone, methanol, ethanol and ammonia. The gas sensors are prepared by solution mixing between non-conducting form of PANi and PMMA in presence of NMP solution. The mixed solution is spun on aluminum interdigitated electrodes and converted into conducting form using HCl doping. Their sensitivity is measured at room temperature by applying constant voltage and measuring response current in the presence of target gases. The results show that PANi/PMMA blend film has higher surface roughness and porous structure leading to higher response to VOCs gases when compared to pure PANi thin film. The PANi/PMMA blend film exhibits the highest response to ammonia and the lowest to acetone vapor. It response shows little different between ethanol and acetone vapor. The different response characteristics to VOCs of PANi/PMMA blend film indicate that it can be used as active layer for room temperature VOCs sensor.

Abstract: In this study, the fringe pattern distribution of various loads on circular disk of homogeneous acrylic in different thicknesses by using reflection polariscope technique was carried out. The load was pressed at the top and the bottom to produce the fringe patterns, which were recorded by digital camera. Then the results were analyzed. The number of isochromatic fringe pattern depends on the magnitude of force acting on the circular disk and these relation is linearly. The application of these research is used to predict stress distribution on the transparent material in the case of different dimension of the circular disk shape.

Abstract: The optical spectroscopic properties of fluorescent materials were investigated using laser induced fluorescence technique. The fluorescent creams were used in this research. The sample materials were illuminated by UV laser excitation source. Then, the fluorescence spectra were recorded and analyzed by fiber optics spectrometer complied with the CIE 1931 XYZ color space which is essential for color management. The result showed that the characteristics of fluorescence spectra such as intensity, wavelength position and bandwidth in each fluorescent creams exhibited distinct characteristics in each species.

Abstract: A chemical precipitation method was used to prepare zinc oxide (ZnO) nanostructure in the present of zinc nitrate and ammonium hydroxide as zinc precursor and hydroxide precursor respectively. The effect of the hydroxide concentration and the effect of adding ascorbic acid as modifier into the mixture solution on the morphology property of zinc oxide was studied. The morphology and the structural of ZnO nanostructures were investigated by field-emission scanning electron microscope (FE-SEM) and X-ray diffractometer (XRD) techniques, respectively. The results showed that the basicity solution and adding stabilizer are important parameters on the morphology and structural properties of ZnO nanostructure. At a low hydroxide concentration, ZnO exhibited flower-like structure with short petal. With a further increase to higher concentration, ZnO crystal have more crystal directional growth. When the ascorbic acid was added, the morphology changed to particle-like structure. ZnO nanostructure with different shape might be used for specific applications such as gas sensor etc.